External risk intelligence

Microsoft Windows Font Parsing Remote Code Execution Advisory.

CVE advisoryKnown Exploit

CVE-2014-4148

A vulnerability in Windows kernel-mode drivers allows for arbitrary code execution through crafted TrueType fonts. This impacts affected systems and data by enabling unauthorized code execution via user interaction with malicious content, posing a business risk.

2Halo Surface Signal

Code Injection

Microsoft Windows 7

External exposure likelihood

Halo Surface Signal score for CVE-2014-4148

This vulnerability exists within the Windows kernel-mode driver (win32k.sys) and requires processing a crafted TrueType font file. While it can be triggered remotely, it typically requires the user to interact with malicious content, such as visiting a website or opening a file, rather than being a directly reachable public-facing network service or appliance portal.

Horizon Alert

Summary of the vulnerability and why it matters

Microsoft Windows operating systems are affected by a vulnerability in the kernel-mode drivers. The flaw allows for the execution of arbitrary code when a specially crafted TrueType font is processed. This could lead to a significant compromise of affected systems and data.

Vulnerable: Windows kernel-mode drivers
Flaw: Improper TrueType font handling
Impact: Arbitrary code execution

Attack Path

How an attacker could exploit the issue

This vulnerability allows attackers to execute arbitrary code on affected Windows systems by sending a specially crafted TrueType font file. The vulnerability is present in the kernel-mode drivers responsible for handling fonts. Exploitation can lead to unauthorized code execution, potentially compromising the system and the data it holds.

External systems can be exposed.
Attacker sends crafted font file.
System executes attacker code.

Live Threat

Current exploitation, exposure, and threat context

This vulnerability allows remote attackers to execute arbitrary code by exploiting how the Windows kernel-mode driver handles TrueType fonts. The exploit requires user interaction, such as opening a malicious file or visiting a compromised website, to be successful. Exploitation in the wild was observed in October 2014.

Likely attacker skill level: Intermediate
Required access or conditions: User interaction required
Business risk or urgency: High

Priority actions

Operational Fix

Recommended remediation, mitigation, and detection steps

This vulnerability allows attackers to execute arbitrary code by sending a specially crafted TrueType font to affected systems. Successful exploitation could lead to a compromise of the system, impacting data integrity and confidentiality. The attack requires user interaction, such as opening a malicious document or visiting a compromised website.

Identify systems processing TrueType fonts.
Restrict font processing and file access.
Update systems and verify.

Frequently asked questions

What is win32k.sys in Microsoft Windows?

Win32k.sys is a core component of the Windows operating system, functioning as a kernel-mode driver. It is responsible for managing the graphical user interface, windowing system, and message handling for all applications running on Windows. It plays a critical role in how your computer displays and interacts with visual elements.

What weakness class does CVE-2014-4148 represent?

CVE-2014-4148 is an example of a "Code Generation" vulnerability, specifically a flaw in how the system handles the creation or modification of code. In this case, the vulnerability, identified as CWE-94, stems from the improper handling of TrueType fonts within the Windows kernel, potentially allowing attackers to execute arbitrary code.

How can CVE-2014-4148 be triggered, and what does not trigger it?

This vulnerability is triggered when a specially crafted TrueType font file is processed by the affected Windows systems. The bug is not triggered by simply having the font file present; it requires the system to actively parse or render the malicious font, often through user interaction like opening a document or visiting a compromised webpage.

Who should care about CVE-2014-4148, considering Halo Surface Signal?

Organizations with internet-facing systems should be particularly concerned about this vulnerability. While the exploitation requires user interaction, meaning it's not a directly reachable network service, the potential for remote code execution on affected Windows machines makes it a significant risk, especially if such systems are accessible from the internet.

What is the first step for responding to CVE-2014-4148?

The primary initial step for managing this vulnerability is to identify all systems running the affected versions of Microsoft Windows. Once identified, applying the vendor-provided security updates is crucial. Verifying that these updates have been successfully installed on all relevant systems will help mitigate the risk.

References

Written by Nicholas Merritt

External-surface CVE analysis and Halo Surface Signal prioritization for Halo Threat Intelligence.